1. Field of the Invention
The present invention relates to a pharmaceutical composition adapted for oral administration, and more particularly a pharmaceutical composition adapted for an active principle of a medicinal product for human or veterinary use, which is insoluble or sparingly soluble in water and oils, such as diacerein (diacetylrhein), rhein or one of their salts, which allows their bioavalability to be improved.
2. Description of Related Art
Diacerein, described in patent FR-A-2,508,798, is a compound whose pharmacological properties have been known for several years and have allowed it to be used as a non-steroidal antiinflammatory medicinal product applicable in the treatment of diseases such as arthrosis. However, diacerein is virtually insoluble in water and in alcohols, this being a drawback for its administration, in particular by injection. Moreover, when it is administered orally, diacerein is not totally absorbed by the digestive tract, and, on account of this incomplete absorption, undesirable side effects may be observed, for example laxative effects.
Various derivatives, pharmaceutical compositions and pharmaceutical forms intended to improve the properties of diacerein or of other medicinal products which are insoluble or sparingly soluble in water have been described in the literature. Thus, for example, patent EP-A-243,968 describes a water-soluble potassium salt of diacerein which can be used in the preparation of compositions for parenteral administration.
Patent EP-A-598,337 describes a composition comprising an active principle of a medicinal product which is insoluble or sparingly soluble in water, incorporated into a crosslinked polymer, a surfactant and an oil, this composition being of improved bioavailability. U.S. Pat. No. 5,225,192 describes a process for preparing a fast-dissolving medicinal product, which consists in incorporating the medicinal product into crosslinked polymer particles which are insoluble but capable of swelling in water, in leaving the product in contact with an organic solvent and in drying under vacuum.
The subject of the present invention is a pharmaceutical composition adapted for an active principle of a medicinal product for human or veterinary use, containing a medicinal product which is insoluble or sparingly soluble in water and oils, in particular diacerein, rhein or one of their salts, which can be administered orally and affords faster and more complete absorption of the active principle into the body, and being of better bioavailability, thus making it possible to reduce or eliminate the abovementioned side effects.
The subject of the present invention is also a novel pharmaceutical composition based on diacerein, rhein or diacerein or rhein salts, which can be administered orally in the form of a wafer capsule or a gelatin capsule, and which is of improved bioavalability when compared with the usual forms.